Biomedical subjects

R E Scott

Publications and source records attributed to R E Scott.

At least 19 recordsLinked to original sources

PubMed2004

Policy implications associated with the socioeconomic and health system impact of telehealth: a case study from Canada.

This research was undertaken to inform future telehealth policy directions regarding the socioeconomic impact of telehealth. Fifty-seven sources were identified and analyzed through a comprehensive literature search of electronic databases, the Internet, journals, conference proceedings, as well as personal communication with consultants in the field. The review revealed a focus on certain socioeconomic indicators such as cost, access, and satisfaction. It also identified areas of opportunity for further research and policy analysis and development (e.g., social isolation, life stress, poverty), along with various barriers and challenges to the advancement of telehealth. These included confidentiality, reimbursement, and legal and ethical considerations. To become fully integrated into the health care system, telehealth must be viewed as more than an add-on service. This paper offers 19 general and 20 subject-specific telehealth recommendations, as well as seven policy strategies.

Alberta↗

PubMed2003

Stable overexpression of specific segments of the P2P-R protein in human MCF-7 cells promotes camptothecin-induced apoptosis.

The stable overexpression of near full-length P2P-R protein in human Saos 2 cells restricts cell cycle progression by inducing mitotic arrest at prometaphase and mitotic apoptosis (Gao and Scott, 2002). Those effects of P2P-R were observed in Saos-2 cells that lack p53 and employ a caspase-3-dependent apoptotic signaling pathway. The current studies were performed to evaluate if overexpression of specific segments of the P2P-R protein promote apoptosis in human MCF-7 cells that contain p53 and employ a different apoptotic signaling pathway. Since segments of P2P-R were found not to induce apoptosis independently, the ability of three different P2P-R segments to promote camptothecin-induced apoptosis was evaluated following their stable transfection and expression in MCF-7 cells. Relative to full-length P2P-R (1-1560 aa), the three P2P-R segments used in these studies included: P2P-R-2 (761-1560 aa), P2P-R-3 (1156-1560 aa), and P2P-R-4 (1314-1560 aa). The results document that overexpression of P2P-R-2 and P2P-R-3 promotes camptothecin-induced apoptosis by three to fivefold when assayed by flow cytometric analysis of apoptotic sub 2n cell populations or by TUNEL assays. In contrast, P2P-R-4 had no effect on apoptosis. These results suggest that the ability of P2P-R to promote camptothecin-induced apoptosis in MCF-7 cells involves a specific region (1156-1314 aa) that exists within P2P-R. The data presented also show that the p53 binding domain of P2P-R overlaps with the apoptosis-associated region and previous studies documented that this region of P2P-R also binds single-strand nucleotides (Witte and Scott, 1997). Therefore, P2P-R-promoted apoptosis induced by camptothecin may be influenced by such interactions.

Animals↗

PubMed2003

The socio-economic impact of telehealth: a systematic review.

We reviewed the socio-economic impact of telehealth, focusing on nine main areas: paediatrics, geriatrics, First Nations (i.e. indigenous peoples), home care, mental health, radiology, renal dialysis, rural/remote health services and rehabilitation. A systematic search led to the identification of 4646 citations or abstracts; from these, 306 sources were analysed. A central finding was that telehealth studies to date have not used socio-economic indicators consistently. However, specific telehealth applications have been shown to offer significant socio-economic benefit, to patients and families, health-care providers and the health-care system. The main benefits identified were: increased access to health services, cost-effectiveness, enhanced educational opportunities, improved health outcomes, better quality of care, better quality of life and enhanced social support. Although the review found a number of areas of socio-economic benefit, there is the continuing problem of limited generalizability.

Bias↗

PubMed2001

Senescence represses the nuclear localization of the serum response factor and differentiation regulates its nuclear localization with lineage specificity.

The differentiation of cultured 3T3T mesenchymal stem cells into adipocytes represses growth factor responsiveness by limiting the nuclear localization of the serum response factor (SRF) that binds to and activates the promoters of growth control genes that contain the serum response elements (SRE), such as junB and c-fos. The regulation of SRF nuclear localization by adipocyte differentiation is specific, because we show that adipocyte differentiation does not repress the nuclear localization of six other transacting factors. To determine if repression of growth factor responsiveness that occurs during senescence also represses the nuclear localization of SRF, we studied normal human WI-38 fibroblasts at low versus high population doublings. The results show that SRF localizes to the nucleus of proliferative cells whereas in senescent cells SRF can not be detected in the nucleus. This result is apparent in both immunofluorescence assays and in western blot analysis. We next evaluated the cellular distribution of SRF in selected human tissues to determine whether the loss of proliferative potential in vivo could have a different effect on SRF nuclear localization. We found that in cells of the small bowel mucosa, differentiation modulates SRF nuclear localization in an opposite manner. Minimal SRF expression and nuclear localization is evident in undifferentiated cells at the base of crypts whereas increased SRF expression and nuclear localization is evident in differentiated cells at the surface tip of the villus. These results together establish that regulation of SRF expression and nuclear localization is important in senescence and differentiation in a lineage specific manner.

Adipocytes↗

PubMed1999

Transformation blocks differentiation-induced inhibition of serum response factor interactions with serum response elements.

The differentiation of nontransformed 3T3T mesenchymal stem cells is a multistep process that is associated with the progressive repression of mitogenic responsiveness to serum growth factors that ultimately results in expression of the terminally differentiated adipocyte phenotype. The repression of serum-induced mitogenesis by differentiation correlates with repression of the serum-inducible transcription of junB and c-fos. In contrast, the differentiation of neoplastically transformed cells does not repress mitogenic responsiveness or junB or c-fos inducibility. Because the junB and c-fos promoters both contain serum response elements (SREs), the current studies tested the possibility that differentiation might repress the ability of serum response factor (SRF) to bind to the SRE in normal cells but not in transformed cells. We now report that differentiation represses SRE serum inducibility using nontransformed cells transiently transfected with pjunB SRE thymidine kinase/chloroamphenicol acetyltransferase (SREtk/CAT) or pc-fos SREtk/CAT containing an intact SRF-binding domain. Adipocyte differentiation of nontransformed cells also markedly represses the ability of SRF to bind to the junB SRE, the c-fos SRE, and other SREs, as determined by mobility shift and gel supershift assays, without affecting the DNA binding characteristics of the nuclear protein SP-1. By comparison, the ability of SRF to bind SRE is not repressed by the differentiation of SV40 large T antigen-transformed 3T3T cells. The results further establish that adipocyte differentiation blocks the nuclear localization of SRF, thus preventing its interaction with SREs in nontransformed cells but not in transformed cells.

Adipocytes↗

PubMed1999

The value of an evaluation framework for telehealth initiatives.

Healthcare managers and policy makers will, in the immediate and near future, make major decisions about the allocation of scarce healthcare resources for telehealth 'solutions'. In our haste to capitalize on what technology can do we may be obscuring discussion and research about what technology should do. For example, currently much attention is being paid to standardization for technological aspects of telehealth. In contrast few efforts have been made to seek standardization in regards to a broad evaluation framework for telehealth. A body of opinion believes that missing in our rush into the on-line world is a systematic approach to research into the human, social, cultural, economic, and political factors associated with healthcare. As a result we lack the tools and experience necessary to assess the true value and implications of telehealth 'solutions'. Developing general guidelines for an evaluation framework, from needs assessment through integrated research to post-study assessment, would greatly enhance the quality of decision making by healthcare managers and policy makers. We propose a model--the Telehealth Integrated Research Model (TIRM)--as the first step in encouraging discussion and development of an internationally accepted standardized telehealth evaluation framework.

Data Collection↗

PubMed1997

The proliferation potential protein-related (P2P-R) gene with domains encoding heterogeneous nuclear ribonucleoprotein association and Rb1 binding shows repressed expression during terminal differentiation.

Terminal differentiation is associated with repression in the expression of the proliferation potential proteins (P2P) subset of heterogeneous nuclear ribonucleoprotein (hnRNP) proteins. We report here the cloning and characterization of a 5173-bp P2P-related (P2P-R) cDNA that contains a 4214-bp open reading frame. Probes to this cDNA detect a single 8-kb mRNA in multiple murine tissues and in proliferating 3T3T cells, but not in terminally differentiated 3T3T adipocytes. Evidence that this cDNA can encode peptides with domains for hnRNP association was established by showing that such peptides are recognized by two monoclonal antibodies known to detect core hnRNP proteins, and by showing that the C130 monoclonal antibody, produced against a cDNA-derived fusion protein, also selectively detects native P2P hnRNP proteins. In addition, P2P-R cDNA-derived fusion proteins bind single-stranded nucleic acids, and a P2P-R cDNA-derived antisense oligonucleotide selectively represses P2P expression. Because terminal differentiation is associated with modulation in Rb1 function, we assayed if products of this cDNA might interact with Rb1. Evidence that the P2P-R cDNA encodes a protein domain that binds Rb1 was established using a glutathione S-transferase fusion protein to selectively precipitate Rb1 from cellular extracts. Data also show that this binding is reduced by competition with the adenovirus E1a protein, indicating that binding occurs through the "pocket" domain of Rb1. These results establish that the P2P-R cDNA encodes protein domains involved in both hnRNP association and Rb1 binding and complement recent reports that localize Rb1 to sites of RNA processing in the nucleus.

Adipocytes↗

PubMed1997

Differentiation, differentiation/gene therapy and cancer.

"Differentiation, Differentiation/Gene Therapy and Cancer" is intended to suggest that an understanding of the cell and molecular biology of cell differentiation should advance the development of new cancer therapies. This article, therefore, reviews four general topics and their relationship to each other: (1) the multistep process of cell differentiation in nontransformed and transformed cells, (2) the use of drugs that induce differentiation in vitro as potential clinical differentiation therapy agents for cancer, (3) the evolving emphasis on gene therapy as a new cancer therapy modality, and (4) the concept of differentiation/gene therapy.

Animals↗

PubMed1997

Induction of AP-1 activity associated with c-Jun and JunB is required for mitogenesis induced by insulin and vanadate in SV40-transformed 3T3T cells.

Insulin and vanadate function as complete mitogens for SV40-transformed murine 3T3T (CSV3-1) cells but not for nontransformed 3T3T cells. Mitogenesis induced by insulin and vanadate in CSV3-1 cells is associated with the induction of the expression of protooncogenes c-jun and junB, two major AP-1 transcription factor components. We now report that both insulin and vanadate induce a significant increase in AP-1 DNA binding activity in CSV3-1 cells but not in 3T3T cells. Gel supershift assays and Western blot analysis using specific antibodies demonstrate that the increased AP-1 binding activity induced by insulin and vanadate in CSV3-1 cells is primarily contributed by an increase in the expression of c-Jun and JunB protein levels. Furthermore, treatment of CSV3-1 cells with antisense oligodeoxyribonucleotides to c-jun or to junB blocks insulin- and vanadate-induced mitogenesis whereas antisense junD oligomers have no inhibitory effects. These results therefore demonstrate that the induction of AP-1 binding activity associated with c-Jun and JunB is required for insulin- and vandate-induced mitogenesis in SV40-transformed murine 3T3T cells. Additional data presented in this paper show that JunD/AP-1 binding activity, which is thought to play a negative role in regulating cell proliferation, is also slightly induced following insulin and vanadate stimulation in CSV3-1 cells. Nevertheless, the ratio of proliferation promoting c-Jun/AP-1 and JunB/AP-1 binding activities to proliferation inhibiting JunD/AP-1 binding activity is significantly increased following insulin and vanadate stimulation. These results therefore support the concept that modulation of the balance of positive Jun/AP-1 and negative Jun/AP-1 activities is important in regulating cell proliferation.

3T3 Cells↗

PubMed1997

Interactions of estrogen- and thyroid hormone receptors on a progesterone receptor estrogen response element (ERE) sequence: a comparison with the vitellogenin A2 consensus ERE.

The identification of hormone response elements in the promoter regions of hormonally regulated genes has revealed a striking similarity between the half-site of the estrogen-response element (ERE) and a consensus sequence constituting the thyroid hormone-response element. Because of the potential for thyroid hormone (T3) to affect estrogen (E)- and progesterone-dependent female reproductive behavior via EREs, we have begun to investigate the activity of an ERE identified in the progesterone receptor (PR) proximal promoter and its interactions with the estrogen receptor (ER) and thyroid hormone receptors (TR). In addition, we have compared ER and TR interactions on the PR ERE construct with that of the vitellogenin A2 (vit A2) consensus ERE. Electrophoretic mobility shift assays demonstrated that TR binds to the PR ERE as well as to the consensus ERE sequence in vitro. Further, these two EREs were differentially regulated by T3 in the presence of TR. T3 in the presence of TR alpha increased transcription from a PR ERE construct approximately 5-fold and had no inhibitory effect on E induction. Similarly, T3 also activated a beta-galactosidase reporter construct containing PR promoter sequences spanning -1400 to +700. In addition, the TR isoforms beta1 and beta2 also stimulated transcription from the PR ERE construct by 5- to 6-fold. A TR alpha mutant lacking the ability to bind AGGTCA sequences in vitro failed to activate transcription from the PR ERE construct, demonstrating dependence on DNA binding. In contrast to its actions on the PR ERE construct, TR alpha did not activate transcription from the vit A2 consensus ERE but rather attenuated E-mediated transcriptional activation. Attenuation from the vit A2 consensus ERE is not necessarily dependent on DNA binding as the TR alpha DNA binding mutant was still able to inhibit E-dependent transactivation. In contrast to TR alpha, the isoforms TRbeta1 and TRbeta2 failed to inhibit E-induced activation from the vit A2 consensus ERE. These results demonstrate that the PR ERE construct differs from the vit A2 consensus ERE in its ability to respond to TRs and that divergent pathways exist for activation and inhibition by TR. Since ERs, PRs, and TRs are all present in hypothalamic neurons, these findings may be significant for endocrine integration, which is important for reproductive behavior.

Animals↗

PubMed1997

Serum deprivation induces SV40 early promoter activity.

Proliferation and the expression of proliferation-associated genes are modulated by changing the serum concentration in the media of cultured cells. To determine if activity of the SV40 early promoter is modulated by serum, we examined the expression of SV40 early promoter driven marker genes in murine BALB/c 3T3T cells following serum deprivation or serum stimulation. SV40-promoter-regulated beta-galactosidase and chloramphenicol acetyl transferase genes were studied following either transient or stable transfection. The results show that serum deprivation of growing cells induces SV40 promoter activity while serum stimulation of quiescent G0 cells suppresses it. Kinetic analyses show a significant induction of the SV40 promoter activity during the first 2 days of serum deprivation which is maintained at a high level for 15 days. The induction of reporter gene expression by serum deprivation was selective for the SV40 early promoter because such an effect was not observed using the Rous sarcoma viral promoter. Nuclear run-off assays further show that the transcription controlled by the SV40 early promoter is approximately twofold greater in cells rendered quiescent by serum deprivation for 72 h than in growing cells cultured in medium containing serum. These results suggest that one reason SV40 T transformed cells commonly fail to undergo quiescence following serum deprivation is that the SV40 promoter is induced.

3T3 Cells↗

PubMed1996

JunD phosphorylation, and expression of AP-1 DNA binding activity modulated by serum growth factors in quiescent murine 3T3T cells.

JunD has been implicated as a negative regulator of cell proliferation. If and how JunD is regulated by growth factors however has not been well investigated. We now report that in quiescent murine 3T3T cells, JunD is present in a hypophosphorylated form, but that when quiescent cells are stimulated to proliferate with serum, JunD undergoes a transient increase in its phosphorylation that occurs within 10 min and persists for up to 4 h. The increase in JunD phosphorylation correlates with the induction of cell proliferation since only those growth factors that promote cell proliferation can induce JunD phosphorylation. Treatment of quiescent 3T3T cells with serum also induces significant decreases in JunD/AP-1 DNA binding activity within 2 h and in JunD expression after 8-48h. However, both hypophosphorylated and hyperphosphorylated forms of JunD can bind AP-1 DNA. These results suggest that serum growth factors can modulate JunD characteristics in a variety of apparently independent ways to overcome its negative regulatory effect in controlling cell proliferation. These include induction of a transient increase in JunD phosphorylation, repression of JunD AP-1 DNA binding activity and downregulation of JunD expression.

3T3 Cells↗

PubMed1996

Hypothalamic cellular and molecular mechanisms helping to satisfy axiomatic requirements for reproduction.

In the absence of universal equations expressing neurobiological findings, the safest theoretical approach for the neuroendocrinologist is to start from axiomatic requirements for biologically adaptive neural mechanisms, in our case for reproduction. From this emerge two themes: the likely importance of interactions between internal (hormonal) and external signals in controlling gene expression relevant to reproductive functions; and, second, the vision of molecular interactions on DNA subserving environmental impacts on reproduction. The first theoretical notion has so far yielded data showing a role for synaptic inputs during the onset of estradiol actions for the hormone's induction of enkephalin mRNA, a finding which parallels earlier behavioral results. As well, noxious somatosensory inputs interact with estrogens and progesterone in their influence on enkephalin gene expression. The second theme led to novel investigations of thyroid influences on reproductive molecular biology and behavior, including the ability of exogenous or endogenous thyroid hormones to reduce female mating responses. Since elevated thyroid hormone levels could signal environmental cold, our experiments offer the possibility of explaining ethological facts at a molecular level. More generally, nuclear hormone receptor interactions on the surface of DNA may offer a new level of neural integration revealed first by hormone effects in neuroendocrine cells.

Animals↗

PubMed1996

Differentiation modulates the balance of positive and negative Jun/AP-1 DNA binding activities to regulate cellular proliferative potential: different effects in nontransformed and transformed cells.

Differentiation of 3T3T cells into adipocytes results in the progressive repression of growth factor responsiveness. This is associated with the transcriptional repression of the inducibility of c-jun and junB expression by serum. In contrast, differentiation of SV-40 large T antigen-transformed 3T3T cells (CSV3-1) does not repress growth factor responsiveness nor c-jun or junB inducibility even though CSV3-1 cells can differentiate into adipocytes. To better explain these observations, we have studied compositional changes in AP-1 DNA binding activity attributed to c-Jun, JunB, and JunD during the differentiation process in 3T3T and CSV3-1 cells. The results show that in nontransformed 3T3T cells, differentiation represses AP-1 DNA binding activity via a proportionate downregulation of c-Jun, JunB, and JunD. In contrast, in CSV3-1 cells, AP-1 DNA binding activity increases twofold during differentiation, which is accounted for by an increase in JunD with no change in c-Jun and JunB. If c-Jun and JunB serve as positive regulators and JunD serves as a negative regulator for cell proliferation as suggested by previous studies, the repression of JunD expression in differentiating CSV3-1 cells should be mitogenic because decreasing JunD/AP-1 DNA binding activity would allow c-Jun/AP-1 and JunB/AP-1 DNA binding activities to be dominant. The results confirm this prediction showing that antisense junD oligodeoxyribonucleotides are mitogenic for differentiating CSV3-1 cells whereas antisense c-jun and junB inhibit mitogenesis. These data support the conclusion that differentiation can regulate cellular proliferative potential by modulating the balance of positive and negative Jun/AP-1 DNA binding activities in distinct ways in nontransformed and transformed cells.

3T3 Cells↗

PubMed1996

Estradiol regulation of nitric oxide synthase mRNAs in rat hypothalamus.

Expression and estrogen regulation of the genes for nitric-oxide (NO)-synthesizing enzymes (NO synthase, NOS) were investigated by in situ hybridization. This study focused on regions of the hypothalamus that contain estrogen receptors and regulate specific neuroendocrine functions related to female sexual behavior and food intake, among others. Ovariectomized (OVX) rats were treated with vehicle or 3 micrograms/100 g estradiol benzoate (EB) for 7 days. Brains were sectioned and hybridized with antisense riboprobes for neuronal NOS, macrophage NOS and endothelial NOS. In the hypothalamus, mRNA was clearly detectable only for the neuronal NOS with the probes used. A strong hybridization signal was observed in the supraoptic paraventricular and ventromedial nuclei (SON, PVN and VMN, respectively). Quantitative analysis showed an increase in neuronal NOS mRNA in the VMN of the OVX rats treated with EB. The increase was mainly in the ventrolateral aspect of the VMN. No significant changes were observed in the hypothalamic SON and PVN. The data suggest that the expression of neuronal NOS mRNA in VMN can be regulated by estrogen.

Animals↗

PubMed1994

Adipocyte differentiation selectively represses the serum inducibility of c-jun and junB by reversible transcription-dependent mechanisms.

Nonterminally differentiated 3T3 T adipocytes are resistant to growth stimulation by 10% (vol/vol) fetal bovine serum even though they can be induced to proliferate with extremely high serum concentrations. We now report that in adipocytes 10% fetal bovine serum also fails to typically induce c-jun or junB. Rather, after 10% fetal bovine serum treatment, c-jun and junB expression is markedly repressed after a brief initial slight induction. Gel mobility shift studies confirm that AP-1 DNA binding activity is inhibited in adipocytes. Repression in c-jun and junB inducibility in adipocytes results from transcriptional mechanisms, can be reversed by treatment with protein synthesis inhibitors or higher serum concentrations, and does not affect c-fos or c-myc expression. These data suggest that adipocyte differentiation selectively and transcriptionally represses the inducibility of c-jun and junB so as to decrease the cell's ability to proliferate in response to 10% fetal bovine serum.

3T3 Cells↗

PubMed1994

Distinct protein tyrosine phosphorylation during mitogenesis induced in quiescent SV40-transformed 3T3 T cells by insulin or vanadate.

Insulin and vanadate selectively induce mitogenesis in quiescent SV40 large T antigen-transformed 3T3 T cells (CSV3-1) but not in quiescent nontransformed 3T3 T cells. Insulin and vanadate mediate this effect in CSV3-1 cells by distinct signal transduction mechanisms that involve protein tyrosine kinase activity. To further study these processes, changes in protein tyrosine phosphorylation induced by insulin and vanadate were investigated. Using immunoprecipitation and Western blotting techniques with antiphosphotyrosine antibodies, we report distinct protein phosphorylation characteristics in insulin- and vanadate-stimulated CSV3-1 cells. The insulin receptor beta-subunit is phosphorylated within 2 min after insulin stimulation of transformed CSV3-1 cells. Insulin also stimulates a rapid increase in tyrosine phosphorylation of the 170 kDa insulin receptor substrate-1 and complex formation between the phosphorylated insulin receptor substrate-1 and the 85 kDa subunit of phosphatidylinositol 3'-kinase. In contrast, vanadate does not initially increase detectable phosphorylation of any proteins, including neither the insulin receptor nor the insulin receptor substrate-1. After 60 min, however, a marked increase in tyrosine phosphorylation of 55 and 64 kDa proteins is observed in vanadate-treated CSV3-1 cells. Furthermore, treatment of CSV3-1 cells with genistein abolishes the effects of vanadate on protein tyrosine phosphorylation but only minimally inhibits the effects of insulin. Finally, insulin stimulates the phosphorylation of a 33 kDa protein, whereas vanadate does not. By comparison, in nontransformed 3T3 T cells, insulin induces a delayed and weaker tyrosine phosphorylation of the insulin receptor beta-subunit and vanadate does not enhance the tyrosine phosphorylation of the 55 and 64 kDa proteins. These data together indicate that the mitogenic effects of insulin and vanadate are associated with distinct protein phosphorylation patterns that appear to be differentially regulated in SV40-transformed and nontransformed 3T3 T cells.

3T3 Cells↗

PubMed1994

Coordinate induction of I kappa B alpha and NF kappa B genes.

The NF kappa B transcription factor exists in an inactive state when complexed with I kappa B alpha in the cytosol. Upon stimulation by a variety of agents, NF kappa B is released from I kappa B alpha and is translocated to the nucleus to induce kappa B motif-containing promoters. Once I kappa B alpha is dissociated from NF kappa B, I kappa B alpha is rapidly degraded. Few studies have been reported concerning the molecular basis for the regulation of I kappa B alpha gene expression. The current studies now show: (1) the expression of I kappa B alpha can be induced by protein synthesis inhibitors including cycloheximide, anisomycin, and puromycin; (2) cycloheximide-dependent induction can be blocked by a transcriptional inhibitor; (3) double-stranded RNA and tumor necrosis factor alpha, which are both known to induce NF kappa B, induce the expression of I kappa B alpha, whereas L-cysteine, which is known to inhibit NF kappa B expression, inhibits I kappa B alpha expression; and (4) the induction of I kappa B alpha gene expression is transient, as is the induction of other NF kappa B-inducible genes. These findings suggest that I kappa B alpha is a NF kappa B-inducible gene. The current results also show a concomitant induction of both subunits of NF kappa B (p50 and p65) after the treatment of cells with double-stranded RNA. Based on these results, a model is proposed suggesting the existence of integrated pathways for the positive and negative autoregulation of I kappa B alpha and NF kappa B.

Amino Acid Sequence↗